This invention relates to wire-in-slot connecting devices of the general type disclosed in U.S. Pat. Nos. 3,854,114 and 3,012,219 and in United Kingdom Pat. No. 615,737 which has an accepted date of Jan. 11, 1949.
Wire-in-slot connecting devices of the general type disclosed in the above-identified publications have been widely accepted in the electrical industry for connecting wires to each other, for connecting individual wires to electrical terminals, and for other uses. Connecting devices of this type are extremely convenient to use for the reason, among others, that it is not necessary to strip the insulation from the wire prior to moving the wire into the slot in the connecting device; the insulation is simply displaced as the wire moves into the slot so that the edges of the slot establish electrical contact with the conducting core of the wire.
A comparative shortcoming of some known connecting devices of the wire-in-slot type is that they are not entirely satisfactory for use with stranded wire and they have been used in the past primarily with solid wire. The difficulties with stranded wire probably stem from the fact that when a stranded wire is forced into a wire receiving slot, the strands tend to separate or splay and distribute themselves along the length of the slot so that they are in side-by-side relationship; they do not remain as a compact mass having a circular or oval shaped cross-section. As a result of this splaying or distribution of the strands, the edges of the slot do not maintain adequate contact pressure against the strands of the wire. Where the wire has only a single strand, the slot can be dimensioned such that its edges do maintain intimate contact with the wire.
In accordance with one aspect of the invention, a wire-in-slot connecting device is provided which is particularly intended for stranded wires. The connecting device comprises a housing and a metallic connector member which has a configuration and other structural features which overcome the problems and difficulties previously encountered with stranded wire connections. Specifically the housing for the metallic connecting device is provided with a means for holding the portion of the wire which is immediately adjacent to the metallic connector member in a compact mass so that the strands which are between the edges of the slot are restrained from moving apart and distributing themselves along the length of the slot with a resulting loss in contact pressure.
In accordance with a further aspect of the invention, there is provided an improved terminal block or junction block for the general type used to make common electrical connections among two or more wires. Junction blocks of this type and having this capability are widely used in a variety of circumstances such as in machines or appliances where the various components of an electrical system including switches, motors, relays etc. must be interconnected.
It is accordingly an object of the invention to provide an improved wire-in-slot type connecting means. A further object is to provide a wire-in-slot connecting means for stranded wires as well as solid wires. A further object is to provide an improved terminal block or junction block which can in a minimum of time be applied to a plurality of wires to form selective interconnections among the wires.